Record numbers of A-level students are expected to achieve their required grades and take up the offer from their top-choice university on results day this week, according to admissions experts, who are warning that this may leave few spaces available in clearing for the most popular courses.

Competition for places is expected to be fierce because teacher-assessed grades, which have replaced exams cancelled by the pandemic, are predicted to result in grade inflation, with higher marks awarded than usual, meaning more students will meet their offers.

Experts said universities were less likely to accept students who narrowly miss their grades on Tuesday, especially on the most popular courses at highly selective universities, where there are concerns about over-recruitment.

Universities are bracing themselves for complaints from angry students and their teachers, who have come to expect flexibility in recent years as institutions have expanded. In particular, universities that accept a high proportion of students from private schools are expected to have an unusually high number of students meet their offers.

Teachers at private schools are expected to award more As and A*s as they usually give higher predicted grades. Last week, the TES reported that the Department for Education feared the attainment gap between private and state school pupils had grown this year due to teacher-assessed grades. If that proves accurate, the proportion of university students who went to a state school is likely to fall.

Students who miss their grades can apply for vacant places through the clearing process, which begins on A-level results day.

“I’m expecting clearing this year to be very busy,” said Jane Harrington, vice-chancellor of the University of Greenwich in south-east London. “We are putting on a lot more phone lines than we’ve had before, we’ll start at 8.30am to reassure people they will be able to get through to a person.”

Her university will be offering fewer places in clearing than in previous years. It is already oversubscribed for health courses. She added that many students are already approaching the university about clearing because they are expecting teacher-assessed marks to more closely resemble predicted grades.

Graham Baldwin, vice-chancellor of the University of Central Lancashire, said universities had been keeping a close watch on applications and acceptances, although it has been difficult this year because students have waited longer than usual to choose their preferred institution. “This isn’t a process that just starts this week, we’ve been monitoring applications to ensure we won’t significantly go over the number of places on courses, but there are some courses where there is high demand which have a greater risk,” he said.

He recommended that students who miss their grades to “not panic” and to get in touch with their preferred university as some courses will still have spaces.

Richard Harvey, director of admissions at the University of East Anglia, said some courses were better placed to cope with over-recruitment than others. “For some courses, extra students aren’t a problem: you can just add an extra seminar group, and maybe you have plenty of accommodation spare. But in some cases you can’t take any more, for instance nursing, medicine and dentistry, so you have to hope that inflation hasn’t taken you over your target.”

In recent years, there have been increasing numbers of places at Russell Group universities available in clearing but these institutions are likely to be more circumspect now.

“If grades are very high, a lot of people will get their first choice at these selective universities, and this Russell Group clearing could be very limited,” said Mark Corver, an admissions expert and founder of DataHE.

Corver predicted that places would mostly be available at universities with average to low entry requirements. “Students open to different subjects will have the widest choice.”

Medicine courses in particular are bursting at the seams because they were heavily oversubscribed this year and there are limits to the number of hospital placements universities can arrange. The Department for Education is said to have asked some universities to accept students redistributed from other courses. Exeter University is prepared to pay some medicine offer-holders GBP10,000 to defer their places, in order to free up spaces on its course, with other universities expected to follow.

David Seaton, assistant director of admissions at the University of Bedfordshire, said applicants should not feel pressed into accepting incentives to defer: “If they meet the conditions of an offer, that university should honour that confirmation.”

Seaton also encouraged students who recently changed school to get in touch with their first choice university in the event they miss their grades, because they may have been disadvantaged by the absence of historical data on their performance relative to peers who have spent longer at the same school.